JPH0639313A - Electrostatic dust collector - Google Patents

Abstract

PURPOSE:To avoid secondary damage of device due to the lowering of insulation resistance caused by a short-circuit accident by providing a device for detecting voltage and current of a dust collecting unit and a charging unit and providing a means for judging the insulation resistance of both unit. CONSTITUTION:In an electrostatic dust collector, since the form of each signal 11-14 outputted from a high voltage power source is 0-1mA, it is inputted into a differential amplifier unit and converted to an output of 0-10V and inputted into a sequencer 16 so as to be easily processed therein. When a start command of the dust collector is delivered, a test voltage is applied to a dust collecting unit and charging unit, and return analog signals 11-14 are processed in the sequencer 16. In a division unit 1, an output voltage signal 11 of the dust collecting unit is divided by an output current signal 12 and the value thus obtained is taken as an insulation resistance value of the dust collecting unit at this point of time and the value and a judgement level value 2 of insulation resistance of dust collecting unit are compared at a comparator unit 3 and if the value is equal to the level value or larger, a start permission command 4 is outputted, and if not, short-circuit alarm 5 is outputted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a means for determining whether the insulation resistance values of a dust collecting portion and a charging portion are good or bad in a control means of an electrostatic precipitator.

[0002]

2. Description of the Related Art In recent years, an electric dust collector is installed in a bypass tunnel formed in a tunnel of an automobile road, and the electric dust collector cleans polluted air in the tunnel.

FIG. 3 is a perspective view showing the basic structure of the electrostatic precipitator, in which 101 is a charging unit, 102 is a dust collecting unit,
103 is a high-voltage power supply unit.

The charging section 101 is provided between a plurality of discharge lines 101A for applying a high voltage of, for example, +11 kV from a high voltage power supply section 103 and a plurality of ground electrode plates 101B arranged between the discharge lines 101A. A corona discharge is caused to charge the suspended particles contained in the contaminated air A passing through the space during this period.

The dust collecting section 102 includes a plurality of high voltage side dust collecting electrodes 102A for applying a high voltage of, for example, +5.5 kV from the high voltage power source section 103, and these high voltage side dust collecting electrodes 102.
A plurality of ground side dust collecting electrode plates 102B arranged between A and A, and the contaminated air A which has passed through the charging unit 101 and charged floating particles therein is charged on both electrode plates 102A and 1A.
02B, the electrode plate 102B
Then, the charged airborne particles in the contaminated air A are collected to obtain clean air B.

On the other hand, a high voltage charging unit to which a high voltage is applied,
That is, the discharge wire 101A and the high-voltage side dust collecting electrode 102
A and the supporting conductors for guiding a high voltage from these high-voltage power supply units 103 are supported in the dust collector by a high-voltage insulator (not shown). It is difficult to completely isolate this insulator from the passage through which the contaminated air A passes, because it is difficult to maintain the electrical insulation of the discharge line 101A, the high-voltage side dust collecting electrode 102A and the supporting conductor. Part of the wire wraps around the insulator. Therefore, suspended particles in the contaminated air A may adhere to the surface of the insulator as dust and reduce its dielectric strength (performance).

In consideration of the above points, as a means for preventing the floating particles in the contaminated air from adhering to the surface of the insulator and maintaining its insulating performance, dust removal at the dust collecting portion by blowing compressed air is performed. At the same time as the work, a so-called air blow method in which compressed air is blown to the insulator to remove dust accumulated on the surface or in the vicinity thereof, and a so-called washing method in which water is blown instead of the compressed air have been conventionally proposed.

However, in the case of removing the dust on or near the surface of the insulator by the above-mentioned air blow method, if a large amount of water is mixed in the compressed air to be blown, the dust on the surface of the insulator can be removed to some extent. Dust adheres to the surface of the insulator due to the water content, and its insulation resistance is likely to decrease. This is because the insulator is washed directly with water in the above-mentioned water washing method, so the insulation resistance value is further reduced compared to the air blow method. Can be easily invited. Moreover, it is difficult to completely remove the dust on the surface of the insulator by both of the above methods, and the dust remaining on the surface of the insulator absorbs moisture from the surrounding atmosphere, resulting in a decrease in the insulation resistance value of the insulator.

In such an electrostatic precipitator, when starting, a voltage lower than the rated voltage is applied to the dust collector and the charging unit for a certain period of time, so that the insulation resistance value of the insulator is lowered by moisture. However, due to the Joule heat due to the leakage current flowing through the moisture absorption portion of the insulator surface, the moisture absorption portion of the insulator is dried and the insulation resistance value is recovered.

[0010]

Since such a conventional electrostatic precipitator does not have the function of detecting and determining the insulation resistance value (especially at startup), is the insulation resistance value lowered due to moisture absorption? , It is not possible to determine whether the insulation resistance value has dropped due to a short circuit accident, and if a short circuit occurs, a high voltage will be applied after startup, which is unsafe and causes secondary damage to the equipment. However, there is a problem in operation control in that it tends to be caused.

The present invention solves the above problems and provides an electrostatic precipitator equipped with a control means for detecting the insulation resistance value of an insulator when starting the electrostatic precipitator and determining whether the insulation resistance is good or bad. The purpose is to do.

[0012]

In order to achieve the above object, the present invention comprises a dust collecting section, a charging section, a voltage / current detecting mechanism for the dust collecting section, and a voltage / current detecting mechanism for the charging section. The configuration of an electrostatic precipitator is characterized in that it has means for judging whether the insulation resistance values of the dust collecting portion and the charging portion are good or bad.

[0013]

According to the present invention, when the electrostatic precipitator having the above-described structure is started, even if a short circuit of about 2 to 5% of the rated voltage is made, there is almost no possibility of causing secondary damage to the equipment. A low voltage is applied as a test voltage to the dust collecting part and the charging part, the insulation resistance value of the insulator of the dust collecting part and the charging part is detected, and if the value is, for example, 10 k to 300 k ohms, the insulation resistance value due to moisture absorption. Therefore, the device is started up while being dried by Joule heat, and if it is less than 10 k ohms, it is determined that the insulation resistance value has decreased due to a short circuit, and a failure is output without starting the device.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 is a control block diagram for carrying out the present invention in an electric dust collector, where 11 is the output voltage signal of the dust collector, 12 is the output current signal of the dust collector, and 13 is the output of the charging unit. A voltage signal, 14 is an output current signal of the charging unit, 15 is a differential amplifier unit, and 16 is a sequencer with an analog signal processing function.

Since the form of each signal of 11 to 14 output from the high-voltage power supply unit 103 is 0 to 1 mA, 0 to 10 are input to the differential amplifier unit 15 so that the sequencer 16 can easily process them.
After being converted to V output, it is input to the sequencer 16.

In FIG. 1, a command to start the dust collector is issued, a test voltage is applied to the dust collector and the charging unit, and signals 11 to 14 as return analog signals corresponding to the test voltage are stored in the sequencer 16. The calculation processing flow processed is shown. 1 and 6 are division units, 2 and 7 are judgment values of insulation resistance of the dust collecting unit and the charging unit, 3 and 8 are comparing units, and 4 and 9 are start permission commands for the dust collecting unit and the charging unit (that is, the dust collecting unit). And high voltage application permission command to the charging section),
Reference numerals 5 and 10 are short-circuit alarms of the dust collecting portion and the charging portion.

In the division unit 1, the output voltage signal 11 of the dust collecting unit is divided by the output current signal 12 of the dust collecting unit, and this value is taken as the current insulation resistance value of the dust collecting unit. The comparison unit 3 compares the insulation resistance determination level value 2 and if the determination level value is greater than or equal to the determination level value (Yes), the dust collection unit start permission command 4
Is output, and if it is less than the judgment level value (if No)
The short-circuit alarm 5 of the dust collecting part is output.

The above is the calculation processing flow of the insulation resistance determination at the time of starting the dust collecting portion.

The charging unit is also the same as the calculation processing flow, and a description thereof will be omitted. The results of an experiment in which the control means of this example was incorporated into a test electrostatic precipitator will be described below.

A moisture absorption state (insulation resistance value 25 k ohms for both the dust collecting portion and the charging portion) and a short circuit state (0.1 k ohm for both the dust collecting portion and the charging portion) are set at the start of the electrostatic precipitator, respectively. When trying to start the dust collector, it was confirmed that the moisture absorption state and the short circuit state could be clearly discriminated.
That is, in the moisture absorption state, if an output voltage that can be changed in an analog manner from the high-voltage power supply unit 103, which is [insulation resistance value] * [current of maximum capacity of the high-voltage power supply unit 103], is applied to each of the dust collecting unit and the charging unit. Since the insulation resistance value decreases due to the drying effect of Joule heat over time, as a result, the output power of the high-voltage power supply unit 103 continuously increases in an analog manner, and the operating voltage (rated voltage) can be safely used without sparking. It has been proved that the output voltage of the high-voltage power supply unit 103 can be increased stepwise using a timer. Further, in the short-circuited state, the short-circuit alarms 5 and 10 of the dust collecting portion and the charging portion are immediately issued, so that the safe operation of the electric dust collector is secured.

As described above, according to the electrostatic precipitator of the embodiment of the present invention, when the electrostatic precipitator is activated, first, a low voltage is applied as a test voltage to the dust collecting section and the charging section, and then the dust collecting section. Further, since the insulation resistance value of the insulator of the charging section is detected and the quality thereof is determined, it is possible to provide a control means for preventing secondary damage to the device due to a decrease in insulation resistance value due to a short circuit accident.

[0023]

As is apparent from the above embodiments, according to the present invention, when the electrostatic precipitator is started, a low voltage is first applied as a test voltage to the precipitating part and the charging part. Also, it is possible to provide an electrostatic precipitator that can detect the insulation resistance value of the insulator of the charging unit and prevent secondary damage to the device due to a decrease in insulation resistance value due to a short circuit accident.

[Brief description of drawings]

FIG. 1 is a flow chart of a calculation process of insulation resistance detection at startup of an electrostatic precipitator according to an embodiment of the present invention.

FIG. 2 is a control block diagram of the same insulation resistance value detection.

FIG. 3 is a perspective view showing a basic configuration of a conventional electrostatic precipitator.

[Explanation of symbols]

1 Division unit 2 Judgment level value of insulation resistance of dust collection unit 3 Comparison unit 4 Activation command of dust collection unit (that is, high voltage application permission command to dust collection unit) 5 Short circuit alarm of dust collection unit 6 Division unit 7 Charging Insulation resistance judgment level value of the part 8 Comparison part 9 Activation command of the band transfer part (that is, high voltage application permission command to the charging part) 10 Short circuit alarm of the charging part 11 Output voltage signal of the dust collecting part 12 Output current signal 13 Output voltage signal of charging section 14 Output current signal of charging section 15 Differential amplifier unit 16 Sequencer with analog signal processing function

Claims (1)

[Claims] 1. A dust collecting unit, a charging unit, a voltage / current detecting mechanism for the dust collecting unit, and a voltage / current detecting mechanism for the charging unit, and determines whether the insulation resistance values of the dust collecting unit and the charging unit are good or bad. Electrostatic precipitator having means.